1. Field of the Invention
The present invention relates to a vision system for an aircraft, comprising:
a display;
an assembly for dynamically generating synthetic images, the synthetic images comprising at least one synthetic surface representation of the terrain situated facing the aircraft;
a management assembly for the graphic interface of the display, capable of controlling the display, on at least a first region of the display, of a peripheral area formed from a synthetic image comprising at least one synthetic surface representation of the terrain coming from the synthetic image generating assembly;
the management assembly being capable of maintaining at least one area representative of the position of a landing runway, centered on the landing runway and at least one front area, adjacent to the centered area, substantially with no synthetic surface representation of the terrain, the peripheral area extending at least partially around the centered area and/or the front area.
2. Description of the Related Art
Such a system is designed to be installed in the cockpit of an aircraft to be associated with a display of the cockpit. The display is for example an at least partially transparent display, such as a semitransparent screen placed in front of the windshield of the cockpit, a system for projecting images on the windshield of the cockpit, a semitransparent sunshade, a helmet visor, or semitransparent glasses close to the eye. Alternatively, the display is a head-down screen integrated into the dashboard of the cockpit.
To facilitate piloting the aircraft, and to give the pilot overall information on the structure of the terrain situated in front of the aircraft, it is known to generate synthetic images of the countryside situated in front of the aircraft, in particular from topographical databases, based on the current position of the aircraft determined by the aircraft's navigation system.
The synthetic images are representative of the environment situated in front of the airplane, as it may be observed through the windshield by a pilot in the cockpit. These synthetic images generally comprise a synthetic surface representation of the terrain.
Such a vision system allows the pilot to visualize the relief that may be located in front of the aircraft, in particular when visibility is low or nonexistent.
Such vision systems provide substantial assistance to pilots, but are sometimes inaccurate, in light of possible errors in the positioning of the aircraft and/or in the topographical data available in the databases. It is therefore necessary to have, in parallel, a real vision of the environment located outside the aircraft.
To that end, enhanced vision systems (EVS) have been developed.
These systems generally comprise a camera placed onboard in the nose cone of the aircraft. The camera, which for example includes sensors operating in the infrared, improves the visibility in front of the aircraft, by detecting the terrain and all structures present on the terrain, for example such as lights present on the runway or around the runway, in particular approach ramp lights.
Based on the image data collected by the camera, a real image of the environment present in front of the aircraft is obtained.
Such vision systems therefore make it possible to confirm the position of the runway relative to the aircraft and/or relative to the environment, and facilitate the pilot's decision when he reaches the decision altitude, at which he must choose whether or not to continue landing.
Hybrid vision systems have also been developed. These systems display both a first region comprising a completely synthetic image, and a second region comprising a real image obtained from an enhanced vision system comprising an infrared camera.
Such a system therefore provide substantial assistance to the pilot in identifying the runway on which he will land. However, the length of the front area on the screen is small, such that the assistance provided to the pilot comes only in the final phase of landing, near the runway, when the pilot has already exceeded the decision height.
Such a system is therefore not fully satisfactory. In fact, when the pilot approaches the runway, but is located at a substantial distance therefrom, the view offered by the system is essentially based on an artificial image, except in the front area adjacent to the runway, over a very small length. The pilot therefore cannot see certain visual details, in particular when he reaches the decision height, at which time he must be able to have a sufficient view of the runway to be able to decide whether he will continue landing or go around.